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UNITED STATES PATENT OFFIOE.

JOHN W. GRENNELL, OF OLIVET, MICHIGAN.

sMmHs Specification of Letters Patent No.

To all whom it may concern:

Be it known that I, JoiiN I'V. CRE'NNELL, of Olivet, in the county ofEaton and State of Michigan, have invented a new and useful Improvementlon Twyers for Smiths Forges; and I do hereby declare that the followingis a full, clear, and exact description of the construction andoperation of the same, reference being had to the annexed drawings,making a part of this specification, in which- Figure l is a perspectiveview of the wind chest, and central partition and Fig. 2, is aperspective view of the hearth plate, de-y tached. The whole is usuallyconstructed of cast iron.

The wind chest A is simply a square box, diminishing in size toward thebottom, and open at the top where it is flanged as at B B B to rest onstone or brick work for stationary, or on east iron legs, after thefashion of a stove, for portable uses; there is also an opening in thebottom (not shown) for cleaning out occasionally, the cover of which isa partof the handle O. This wind chest is divided into two chambers orcompartments by the partition D and the hearth plate Fig. 2. Thepartition D has a rotating disk valve on its under side (operated by therod E) with four holes (two of which are shown at F F) for the purposeof regulating the intensit-y of the blast, and on its upper side is atwo way groove formed by the chamfered ribs G G G G, standing at a rightangle; the width of said groove being equal to the side of the largestsquare of the twyer nozzle when fully expanded; these ribs are chamferedto a proper angle, to facilitate the upward direction of the blast. Inthis groove slide the two sectional chamfered nozzle pieces H H withangular slotted openings, as at I, conforming with the ohamfer of theribs G G; they are open underneath to the partition D, which is piercedwith two holes similar to those at F F. These nozzle pieces are moved byrods passing through the sides of the wind chest, and have rims J Jchamfered to correspond with the two stationary ones J J Fig. 2, on

FORGE.

16,531, dated February 3, 1857.

the hearth plate around the two sides of an equilateral opening K equalto the largest extension of the nozzle, plus the width of the cornerblock L, which is chamfered on two sides to correspond with the rims J JJ J. This block L forms a two wayed slot in which slide the projectingrims J J of the sectional nozzle pieces H H.

The ingress passage being below the partition D, the wind passes by thefour valve openings through said partition into the upper compartmentformed by the hearth plate, and issues through the four egress passagesformed by the two slots I I, in the sectional nozzles and the two spacesleft between the under side of the hearth plate and the chamfered ribs GG Fig. 1.

The peculiar advantage of this improvement is, that by the use of thetwo sliding nozzles H H the workman is enabled, not only to increase ordiminish the area of a square formed by the four egress passages; butalso, to cause the orifice to assume the form of a parallelogram,diminishing in width, at pleasure to a mere line, and extending ineither a longitudinal or transverse direction across the forge. The mostdelicate operations of welding can thus be performed with great economyof fuel, and reduced risk of injury by overheating portions of metalthat! would otherwise be continually endangered.

IVhat I claim as my invention and desire to secure by Letters Patent is-The use of the two hollow sectional nozzle pieces H H moving at rightangles in a two way groove formed by the chamfered ribs G G G G Fig. l,in combination with the two wayed slotted opening K in the hearth plateFig. 2, formed and bounded by the stationary rims J J and the chamferedcorner block L whereby the moving nozzles can slide past each other andform a continuous joint in any position.

J. W. ORENNELL.

Witnesses:

GEORGE JOHNSON, JOSEPH C. FUsIK.

